By Richard Black
BBC environment correspondent in Ulsan, South Korea
Pro-whaling nations lost a fourth vote at the International Whaling Commission meeting - one which could have led to a resumption of commercial whaling.
The annual meeting is being hosted this year in Ulsan
The proposal, drawn up by Japan, had been condemned by conservation groups as "totally unacceptable".
Its adoption would have needed a majority of three-quarters at the meeting in Ulsan, South Korea.
But a simple majority in favour would have implied some moral backing for Japan's case.
Earlier in the day, developing countries halted discussions for more than an hour as they protested against "bias and discrimination".
The Revised Management Scheme (RMS) is the most important issue before the IWC.
It is designed to replace the current moratorium on commercial whaling, introduced in 1986 as the evidence became undeniable that many whale stocks were at critically low levels.
Originally mooted in 1992, the RMS would set sustainable catch limits for different whale species based on scientific knowledge of their population levels and behaviour.
It should in theory be a compromise between pro-whaling nations, led by Japan, and the anti-whaling bloc, with Australia, New Zealand and Britain at the helm.
But discussions over the RMS have been endless, the divisions unbridgeable.
Many drafts have existed that have differed in several important ways, including how many observers should be on board whaling vessels to ensure that procedures are followed, where those observers should come from, and whether DNA samples should be taken from whales for matching against meat in the market.
Some conservation groups are adamant that none of these versions have been up to the task of protecting whales from over-exploitation, while other groups have found good things in some of the drafts.
But the various organisations are united in their loathing for the current Japanese version, which lost by a margin of six votes.
"The RMS proposal by Japan was inherently flawed," said Dr Susan Lieberman, director of the species programme at WWF.
"In essence it was an attempt to hoodwink the international community by re-opening commercial whaling without putting any real safeguards in place."
Further discussion of the RMS, including perhaps votes on how to take other versions of the text forward, may come later in the meeting.
Earlier in the day, the deep suspicions within the organisation, which was set up in 1946 to "manage" whaling, and which pro-whaling countries accuse of excessive concern with whale protection, boiled over into open anger.
A few minutes after the start of business, St Lucia's Agriculture, Forestry and Fisheries Minister Ignatius Jean proposed a motion to adjourn the plenary session and take the commissioners into private consultation.
He said that "proper process" had been abused in the previous day's discussions - developing countries had suffered bias and discrimination, he said.
"There were some strategies being employed by Australia and New Zealand in particular aimed at manipulating the Chair," he told reporters.
"This is an august body and countries should be given an opportunity to speak; what was being employed was a strategy to call for a vote every time to shut certain countries up."
A number of developing countries, including St Lucia and other Caribbean states, had voted with pro-whaling Japan on three motions on the first day, all of which were narrowly defeated.
The Brazilian delegation, which usually votes in favour of conservation measures and against pro-whaling propositions, described the adjournment as a "farce".
Having walked out of the closed meeting, Brazil's commissioner Maria Teresa Pess§a told BBC News that it was a waste of time.
"They are discussing conduct of the meeting yesterday; so why wasn't the commissioners' meeting called for first thing this morning before the plenary session began?
"It's a measure to stall the meeting, to wait until new faces arrive, until payments are made."
Four developing countries, Cameroon, Gambia, Nauru and Togo, joined the commission just before the meeting opened. Conservationists had believed they would side with the pro-whaling bloc, tipping the balance of power in their favour.
However, it emerged that of the four, only Cameroon had turned up and paid its subscriptions, enabling the anti-whaling countries to carry the first day votes.
St Lucia's Ignatius Jean denied any connection between his motion and the voting balance.
"It had nothing to do with any of the issues on the agenda; it simply had to do with procedural matters," he said.
There is palpable frustration on both sides over procedures and other issues.
With the RMS apparently deadlocked for the foreseeable future, there are murmurings from several delegations about whether the commission itself needs to be re-thought at ministerial level.